My guess is that your integer fields & date field do not like to be empty (supportID, addrCode and dateInv). I'd start there. If they need to be required, I'd scrub the form data and force a default value that means nothing (-9999 / '1900-01-01').
This works... (Form payload)
[{"geometry":{"x":796086.8072222222,"y":1176275.4861111112,"spatialReference":{"wkid":3435}},"attributes":{"address":"test","supportId":"1","type":"Single Post","size":"12in. tube","material":"","base":"","rating":"","dateInv":"2015-04-22","inspector":"K. Morgan","comments":"","addrCode":"1"}}]
While this fails... (Form payload)
[{"geometry":{"x":796086.8072222222,"y":1176275.4861111112,"spatialReference":{"wkid":3435}},"attributes":{"address":"test","supportId":"","type":"Single Post","size":"12in. tube","material":"","base":"","rating":"","dateInv":"","inspector":"K. Morgan","comments":"","addrCode":""}}]
Pretty please...
Also, you will want to delete all of the records near that geometry ("geometry":{"x":796086.8072222222,"y":1176275.4861111112,"spatialReference":{"wkid":3435}}) with "inspector" 'K. Morgan'. Tried to pick an area where there wasn't any edits for clean-up purposes.